1. Field of Invention
This invention relates to toys, more particularly to a toy helicopter adapted to be forcibly propelled into the air, and further adapted, at or before reaching its point of highest possible ascent to invert itself and rotate with its blades outspread during its return to the ground. Uniquely the present invention device requires no releaseable hold mechanism to assist in the deployment of the helicopter blades at the high point of its trajectory.
2. Description of Prior Art
Catapulted or projected aerial toys commonly are delicate to adjust, unsafe due to high mass, easy to break or bend, and usually require a large area in which to perform. Gliding toys are usually difficult for the lay person to adjust in order for their performance to create the enjoyment of predictable flight.
Toy helicopters offer the best possibility of inexpensive predictable flight provided a reliable control system causes the helicopter blades to deploy at the most favorable moment after the launch, which is usually made from the ground.
U.S. Pat. No. 2,044,819 discloses a "projectile" utilizing three helicopter blades to cause a slow descent but the blades necessarily have a curvature to match the cylindrical shape of the bomb or mortar projectile. Also the copter blade deployment method is immediate upon exposure to the high velocity airstream as the projectile leaves the aircraft from which it must be launched.
The U.S. Pat. No. 2,746,207 is a medium mass device promising to perform very closely to the claims of the present patent, however, the design is inverted, having the outside tip of the blades before launch at the forward part of the device and requiring a releaseable hold mechanism that complicates, adds mass, and reduces streamlining. Spinning about the projected flight axis during ascent is not a necessary part of the helicopter blade deployment function, in contrast, the present invention deploys its helicopter blades partially as a result of spin during the launch part of the flight.
The article disclosed in U.S. Pat. No. 3,113,398 uses magnets and electromagnets that move in a tube as part of an intricate helicopter blade deployment mechanism, in contrast to the simple mechanism herein presented.
The projectile of U.S. Pat. No. 3,188,768 is a complicated high mass toy which consists of helicopter blades that serve as part of the elongated body of the three dimensional device.
The toy projectile in U.S. Pat. No. 3,691,674 has low mass and can ascend to a high altitude but the descent function is not as interesting as it is not required to transform into a second mode of flight and it spins about a horizontal axis instead of vertical axis as a true helicopter would. Also its rate of descent would necessarily be faster or less predictable.
U.S. Pat. No. 3,826,037 teaches a very complicated medium mass toy device using springs, latches, and delicate levers for the purpose of deployment of the helicopter blades. Axial spinning is not a necessary ingredient of its function.
The toy disclosed in U.S. Pat. No. 3,903,801 is of medium mass, partially due to the design that calls for helicopter blades to be protected from the airstream on the ascent, and the addition of a "blow-out charge" that initiates deployment of the helicopter blades for descent.
U.S. Pat. No. 4,295,290 teaches a multistage device that initiates deployment with a chemical "thrust charge".
The U.S. Pat. No. 4,913,675 is a medium mass, up ascent and up descent device (i.e., it doesn't "nose over" at the apogee of its flight) utilizing a releasable hold mechanism for helicopter blade deployment.
All the toy helicopters heretofore known suffer from at least two of the identified disadvantages below:
a) lack of sufficient streamlining that would enable the launch of a low mass device to project it to a high enough altitude before copter deployment for the purpose of generating sufficient play value.
b) drawings imply materials used to be of wood, or dense plastic or metal causing high mass constructions which create a safety hazard for uncontrolled flying toys. High mass devices simply weigh more and can cause more severe personal injury or property damage during a misdirected launch.
(c) due to the utilization of aforementioned construction materials, higher manufacturing costs in the form of heavier more costly equipment to cut, mold, decorate, assemble and transport the final device are incurred.
d) cylindrical main bodies require the helicopter blades to be curved along their chord if external, otherwise they will interfere with the launch aerodynamics. Curved blades are usually more costly to manufacture than flat blades.
e) releaseable hold mechanisms on a toy of this size and scope demand delicate precise construction and adjustment. On a device that will occasionally impact an immovable object, such impact may damage the delicate release hold mechanism.
f) lack of adjustability of the timing of copter blade deployment during launch for the purpose of using the device in a limited air space such as in a back yard.
(g) many of the prior art devices are not rugged enough to sustain many flights due to the aforesaid selection of materials for construction in contrast to the present low mass invention. The high mass of most prior art causes high angular or rotational velocity during descent, sometimes in high wind, over a hardened abrasive surface such as asphalt, resulting in rapid degradation of several important parts including blade tips and release hold mechanism.
(h) through experimentation it has been found that the angle of the axis of the main body of the device during ascent relative to the angle of the motion or vectored angle of the center of mass of the main body if not aligned (non-aligned), can cause wobble and premature deployment of helicopter blades.